Lattice energy Transitional Reasoning Download PDF

Questions

1. 1.

   A materials engineer evaluates four binary ionic solids—$\text{MgO}$, $\text{CaO}$, $\text{NaCl}$, and $\text{KCl}$—to select the compound with the greatest lattice energy for high-temperature furnace insulation. By analyzing the periodic trends in ionic charges and ionic radii, the engineer models the electrostatic interactions within each crystal lattice. Which statement correctly identifies the compound with the greatest lattice energy and provides the valid scientific justification based on Coulomb's law?

   • A) $\text{NaCl}$ exhibits the highest lattice energy because monovalent ions pack into a tighter cubic arrangement that minimizes cation-cation repulsion.
   • B) $\text{MgO}$ exhibits the highest lattice energy because the electrostatic potential energy is predominantly dictated by the higher ionic charges ($+2$ and $-2$), combined with a smaller interionic distance than $\text{CaO}$.
   • C) $\text{CaO}$ exhibits the highest lattice energy because the larger ionic radius of $\text{Ca}^{2+}$ increases ionic polarizability, thereby significantly enhancing overall crystal cohesion.
   • D) $\text{KCl}$ exhibits the highest lattice energy because the lower charge density of potassium and chloride ions allows for maximum coordination number and minimal electrostatic strain.